Experts fear a repeat of an outbreak 25 years ago in which more than 700 bottlenose dolphins died

Reuters/USFW

A virus similar to measles in humans is being blamed for the deaths of hundreds of Atlantic bottlenose dolphins.

Experts at the US National Oceanic and Atmospheric Administration say the Morbillivirus infects the lungs and the brain, causes pneumonia and abnormal behaviour, and is often fatal.

The outbreak has killed 333 bottlenose dolphins in the mid-Atlantic region since July, and may last for a year, possibly being worse than an outbreak 25 years ago which killed more than 740 animals.

Teri Rowles of the NOAA Fisheries Marine Mammal Health and Stranding Response Program says experts are worried about a repeat of those deaths.

"We are expecting that if indeed this plays out the way that die-off occurred, that we are looking at mortality being higher and morbillivirus spreading southward and likely continuing until spring of 2014," she said.

Nine times the average number of dolphins have washed up along the shores of the east coast this summer.

Most of the dolphins found on beaches have already been dead, suffering lesions on the skin, mouth, joints and lungs.

Viruses in the same family can cause measles in humans and canine distemper in dogs and wolves, and typically spread among animals in close contact.